Telegraphic receiver.



E. W. MAYFIELD, DECD.

G- MAYHELD, ADMINISTRATOR.

TELEGRAPHIC RECEIVER.

APPLICATION FILED MAY 29. 1916.

Patented May 21, 1918.

rv v TA Efs Ail- OF E i To (ill whom it may concern: y y I Be it known that I, EDWIN WELLINGTON "sidingat Chicago, in the countyofCook :5 and State ofiIllinois have invented a certain ne nd useful Improvement in Telegraphic Rec 1's; of which thefollovving 1s a full, I cie'a r oncise, Jand exact description, refer "c l hnceheinghad to the accompanying draw: ings, forming a part of this specificat on. My invention relates to telegraphy and a aitiula'rlyi'to a telegraphic receiver; adlyith'e object of my invention IStO fprov i'de mprovedl means for receiving telel '5 gr' phie signals .with sp eed and v secrecy and ihiI'iirnunri of discomfort to the receiving *g' fg 'wr ywgm on il W e is a general demand for speed and graphic communic'ations, particularly ,ror *ce'vijigltelegrams in hotels, brokers" ofiices therpublic' or semi public places.

been proposed heretofore to employ rd 'ai y"telephonewi-eceiver directly in ivingcircuit of the "telegraph *as a find that this is wholly iinpra'cto the l'intense sharpness of the breaks of currents and thepainful eeafr ofitheyoperatorr The 'ver is relatively a very sensipowerful instrument responding glyto 'current changes of infinitesimal gnituuemns the receiver "would; 1n practice, be necessarily clamped upontheear of 235 the user in order to render thesi'gnalsjjsecret, pbwerrul respgine of th'ei rceiver tothe P Tie/leg? on" itio'n "that would" be T wholly "unbearable. g he Wave front of atelegraphic ls excessively sharp, but also the enrgy f'thepurrent istoo great to be permit- I 1 d to operatejdirectly upon the diaphragm the ec iver; ;The sounds of the breaks re intense and sometimes more so than hc'seefi the inakes and the signal's'are indisinguishableas'so; received. addition the p'niaking and breakingof 'thecurrents a ccoinpanied by high"f'frequency 'vibra- I rovertones thatare distinctly unpleas- 5o ant $331M l 3 I I have according to "my inventioui i interti fitai ew fi minim cewe ifiimibi LGO DYM a a i hen or SAID EDWIN WE LINGTONMAYFIEL DECEASED.

AYFIIELD, a citizen ofgthe United States, rep telligible and at -the sameume isplea sant to the ear. I

I secrecyforfreceivinglcertaihg classes of teleaphic impulses would produce "a i J lpose'dgnean fordiminishing the effect oi the YEIELE ADMINIS- rarmaarn EEcEIvEE;

a saa'a aia of LeEtersiPatnt-u Patented 121, 1913 a Application filed May as, 19113; Serial a). 100,456.

understanding of the telegraphic signal and such, othervibrationsbr overtones as are unpleasant to theear. TlllS produces a resulting vibration" which is surprlsmgly -1n- Thefpart icular means that I may employ to secure this screening effect will now be de: scribedin-connection With the accompanying drawings gvvhich illustrate one embodiment. ojmyinvention, It is to be understood that] I do; not intend to be'limited to the precise details shown or describead, and'that the di mensionsand proportions arenot of. the essence of the invention'exceptas the sameare set out in the accolnpanying claims. v a

; Figure 1 isa diagram ofthe. circuit-eniployed in connection with my invention; Fig, 2 is a;'side elevation of the means for transferring the-I signal impulses from the telegraphiccircuit to the telephone circuit Withjth'e; casingshovvn section} v ig. 3' is an' end elevation of themicrophonic device and n v -Fig- 45- isa cross section taken on the line H0fFig-2q y a a; ,t

Ihave foundrthat in receiving telegraphic impulses it is essential; to receive thesharp staccato sound of the barzstriking upon the a. anvil when the circuit is made, but that it is not so essential to receive the sound of the ba'riorstriker moving against the stop. a In other' words, ifthesound of the make inlthe telegraphic circuit is clearly transmitted, signals are readily intelligible I even though the sound of the break is greatly reduced. In carrying outrmy invention" I provide theusualor any preferred telegraph'sounder giving the conventional signal upon the usual make and" break in the telegraph circuit and employinga sensitive device such as -ainicrophone tuned tparticularly tothe sound tithe-bar striking the anvil for a make in *thetel'egraph circuit. To this end I employ :the sounder -1 connected in the telegraph circuit 2 which is provided with a suitable kyor other circuit controlling device 3-and orously to the makes in the circuit and to respond less vigorously for breaks in said circuit.

4. In combination a base, a standard, a microphone electrode secured to said standard, a pair of standards adjustable relative 3 to each other secured to said base, a thin sheet of metal secured to said standard, said sheet of metal being connected to the co brate saicl sheet of metal through the air only and a substantially sound proof shell iwinclosing said sounder and said sheet of metal.

5. In combination, a telegraphic sounder,

a base, a pair of laterally adjustable standards on said base, a third standard arranged adjacent first said standards, a microphone carried by said first standard, a strip of metal extending between first said standards and connected thereto, said microphone having mechanical connection with said strip at its intermediate portion, means to adjust said standards to regulate the responsiveness of said strip to various sound frequencies, and a hood to confine and direct the sounds from said telegraphic sounder to said strip.

In Witness whereof, I hereunto subscribe my name this 26th day of May, A. D. 1916.

E. WELLINGTON MAYFIELD.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of latents,

Washington, D. G. 

